The present invention relates generally to devices and methods for treating occluded or stenoic blood vessels. More particularly, the present invention relates to devices and methods for providing temporary placement of a filter in a blood vessel during a procedure to remove an occlusion or stenosis.
It is critical that the heart muscle be well oxygenated so that the blood pumping action of the heart is not impaired. Blood vessels which have become occluded (blocked) or stenotic (narrowed) may interrupt the oxygen supply to the heart muscle.
Occluded or stenotic blood vessels may be treated with a number of medical procedures including angioplasty and atherectomy. Angioplasty techniques such as percutaneous transluminal angioplasty (PTA) and percutaneous transluminal coronary angioplasty (PTCA) are relatively non-invasive methods of treating a stenotic lesion. These angioplasty techniques typically involve the use of a guidewire and a balloon catheter. In these procedures, a balloon catheter is advanced over a guidewire such that the balloon is positioned proximate a restriction in a diseased vessel. The balloon is then inflated and the restriction in the vessel is opened. During an atherectomy procedure, the stenotic lesion is mechanically cut or abraded away from the blood vessel wall using an atherectomy catheter.
During atherectomy procedures, stenotic debris that is separated from the stenosis may be free to flow within the lumen of the vessel. If this debris enters the circulatory system, it may facilitate the formation of an occlusion in the neural vasculature, or in the lungs, both of which are highly undesirable. An occlusion in the neural vasculature may cause a stroke, and an occlusion in the lungs may interfere with the oxygenation of the blood. During angioplasty procedures, stenotic debris may also break loose due to manipulation of the blood vessel.
The present invention relates generally to devices and methods for treating occluded or stenoic blood vessels. More particularly, the present invention relates to devices and methods for providing temporary placement of a filter in a blood vessel during a procedure to remove an occlusion or stenosis. A filter delivery system in accordance with one exemplary embodiment of the present invention includes a catheter having an elongate shaft and a tubular member disposed within a shaft lumen defined by the elongate shaft. The elongate shaft also includes a proximal end, a distal end, and a wall defining the shaft lumen. The tubular member has a first end fixed to the wall of the elongate shaft, and a second end disposed within the shaft lumen. The tubular member defines a guidewire lumen that is in fluid communication with a distal guidewire port defined by the second end of the tubular member. The catheter also includes a proximal guidewire port extending through the wall of the elongate shaft.
A filter may be disposed within a distal portion of the shaft lumen. A distal end of a guidewire is preferably fixed to the filter. The guidewire preferably extends through the distal guidewire port, the guidewire lumen, and the proximal guidewire port. The elongate shaft of the catheter may be moved proximally relative to the guidewire so that the filter is disposed outside of the shaft lumen. The filter is preferably free to assume an expanded configuration when it is outside of the shaft lumen.
The catheter may be moved relative to the guidewire, for example, by grasping a proximal portion of the guidewire and applying a pulling force to a hub of the catheter. The pulling force may be applied to the hub until the filter is deployed in the expanded configuration. The pulling force may also be continued until the catheter is removed from the blood vessel. Once the catheter has been removed from the blood vessel, the guidewire may be utilized to guide additional catheters (e.g., balloon catheters, atherectomy catheters, etc.) as they are advanced through the blood vessel.
A wire gripper may be used to aid in grasping the guidewire. One exemplary embodiment of a wire gripper includes a handle and a plurality of jaws for grasping the guidewire. A knurl nut fitting is used to urge the jaws against the guidewire.
An additional exemplary embodiment of a filter delivery system in accordance with the present invention includes a catheter having an elongate shaft and a hub disposed about the elongate shaft proximate the proximal end thereof. A slider is disposed in sliding engagement with a cavity of the hub. The slider includes a wire lock having a plurality of jaws. The wire lock may be used to selectively fix a proximal portion of a guidewire to the slider. A distal end of the guidewire is preferably fixed to a filter which is disposed in a shaft lumen of the catheter.
During a procedure to deliver the filter to a target location in a blood vessel, the hub and the shaft of the catheter may be moved proximally relative to the slider and the guidewire. When the hub is moved proximally relative to slider, the filter is urged out of the shaft lumen of the catheter. Once the filter is out of the shaft lumen it is free to assume an expanded configuration. The sliding relationship between the slider and the hub gives the user of the filter deployment system a defined distance to move the slider relative to the hub when deploying the filter.
Yet another exemplary embodiment of a filter delivery system in accordance with the present invention includes a catheter having an elongate shaft including a proximal portion, a distal portion, and a longitudinally collapsible portion disposed between the proximal portion and the distal portion. A ring is fixed to the distal portion of the elongate shaft distally of the collapsible portion. A pull wire is disposed within a shaft lumen defined by the elongate shaft. The distal end of the pull wire is fixed to the ring and the proximal end of the pull wire is fixed to a slider. The slider is disposed in sliding engagement with a hub that is disposed about a proximal end of the elongate shaft. In a preferred embodiment, the slider and the pull wire may be used to selectively collapse the longitudinally collapsible portion of the elongate shaft. The collapsible portion of the elongate shaft is preferably collapsed by urging the slider proximally relative to the hub. In a preferred method, the guidewire is held stationary relative to the slider, while the slider is moved proximally.
A filter retrieval system in accordance with an exemplary embodiment of the present invention includes a retrieval catheter which may be utilized to retrieve a filter that was previously delivered to a target location in a blood vessel. The filter may be delivered to the target location, for example, using a filter delivery system in accordance with an exemplary embodiment of the present invention.
During a retrieval procedure, the retrieval catheter may be advanced along the guidewire until a distal end of the catheter is proximate the filter. In a preferred embodiment, the catheter includes an elongate shaft and a cone disposed at a distal end of the elongate shaft. The cone preferably has a generally tapered shape that may aid in advancing the catheter through the blood vessel. Also in a preferred embodiment, the cone comprises a flexible material, allowing the cone to deflect as the filter is drawn through an aperture defined by the cone. Embodiments of the cone are possible in which the cone is adapted to fold proximally. Embodiments of the cone are also possible in which the aperture of the cone is adapted to expand radially as the filter passes through the aperture. The distal end of the catheter may be advanced distally relative to the guidewire so that the filter is disposed within a shaft lumen of the catheter.
An additional exemplary embodiment of a filter retrieval system in accordance with the present invention includes a catheter having an elongate shaft and a hub disposed about the elongate shaft proximate the proximal end thereof. A slider is disposed in sliding engagement with a cavity of the hub. The slider includes a wire lock having a plurality of jaws. The wire lock may be used to selectively fix a proximal portion of a guidewire to the slider. A distal end of the guidewire is preferably fixed to a filter which is disposed within a blood vessel.
During a filter retrieval procedure, the hub and the elongate shaft of the catheter may be moved distally relative to the slider and the guidewire. During the movement of the elongate shaft, the longitudinal position of the filter is preferably fixed by the guidewire, since the proximal portion of the guidewire is fixed to the slider by the wire lock. As the catheter is advanced distally, it preferably engulfs the filter. The sliding relationship between the slider and the hub gives the user of the system a defined distance to move the slider relative to the hub when retrieving the filter.
Yet another exemplary embodiment of a filter retrieval system in accordance with the present invention includes a catheter having an elongate shaft including a proximal portion, a distal portion, and a longitudinally expandable portion disposed between the proximal portion and the distal portion. A ring is fixed to the distal portion of the elongate shaft distally of the expandable portion. A push rod is disposed within a shaft lumen defined by the elongate shaft. The distal end of the push rod is fixed to the ring and the proximal end of the push rod is fixed to a slider. The slider is disposed in sliding engagement with a hub that is disposed about a proximal end of the elongate shaft. In a preferred embodiment, the slider and the push rod may be used to selectively expand the longitudinally expandable portion of the elongate shaft. The expandable portion of the elongate shaft is preferably expanded by urging the slider distally relative to the hub. In a preferred method, the guidewire is held stationary relative to the slider, while the slider is moved distally. When this is the case, the filter is preferably engulfed by the distal portion of the catheter.